<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>盒子模型</title>
    <style>
        div {
            width: 200px;
            height: 200px;
            margin: auto;
        }

        .d1 {
            background-color: lightgoldenrodyellow;
        }

        .d2 {
            background-color: lightsalmon;
        }

        .s1 {
            display: block;
            width: 300px;
            height: 200px;
            background-color: lightseagreen;
            text-align: center;
        }

        /* img{

        } */
    </style>
</head>

<body>
    <div class="d1"></div>
    <div class="d2"></div>

    <span class="s1">今天晚上有作业</span>
    <input type="text">
</body>

</html>